Technical Field
The present invention relates to an exhaust heat recovery device.
Related Art
There is the technique of raising the temperature of engine cooling water or the like by using the heat of the exhaust from the engine of an automobile. For example, Japanese Patent Application Laid-Open (JP-A) No. 2007-100665 discloses, in an exhaust structure that returns some of the exhaust of the engine to the intake side, a structure that enables heat exchange between cooling water and the exhaust without circulating the exhaust to the intake passage, by opening an opening/closing valve of a bypass passage even at times when the temperature of the engine is low.
Further, JP-A No. 2006-312884 discloses an exhaust heat recovery device that has a heat exchange path having a heat exchanger, and a bypass path that bypasses the heat exchanger. The flow path of the exhaust is switched by controlling a valve body that is provided at the bypass path.
When the flow path of exhaust is switched by control of a valve body (an opening/closing valve) as in JP-A No. 2007-100665 and JP-A No. 2006-312884, there is the need to sufficiently consider the durability of the actuator and the like that drive the valve body by repeating driving of the valve body, and accordingly, the durability of the exhaust heat recovery device.